Bulletproof, with the sport, yes, you would still be able to mount an optic even though it has iron sights. However, if you use a red dot, the front sight post will be visible and will look something like this:
It doesn't make it harder to shoot or anything, and in the event that your red dot runs out of batter you can still use your flip-up iron sights so I like it.
Sent from my HTC One X